Loops are small segments of sound tracks that are repeated continuously. A sound sample that keeps repeating and it is used mostly in electroacoustic music but also in hip hop, trip hop, techno, drum and bass, and contemporary dub, as well as into mood music on soundtracks.

Why to use loops?

In modern music the usage of loops has become very common. This is because they allow you to create music without owning a music instrument or having to learn how to play one.
Also, they can be used continually, and not have the quality degradation that is inherent when musician play a musical part repeatedly (human error). Additionally there can be huge cost savings, on the production end.